😉 FearOrLove gives excellent advice. It does depend a little on the specifics and how and when you use the IDE drives. HDs like to be master, and setting one to slave can limit its throughput to the master device. However, most CDRW like to be master, modern CDRW with burn-proof technology shouldn't mind too much though. You certainly want your main boot HD as the Primary Master, your 2nd HD is unlikely to enjoy being a slave to your CDRW so that means either put the 2nd HD as Sec Master and then use your CDRW as slave (to the HD least likely to be used in conjunction with the CDRW) or put your CDRW as the Sec Master and your 2ns HD then really has to be slave to your 1st HD (not good if you are likely to use both HDs simultaneously). You have to make some compromises however you set them up, about time the IDE interface was revised, 4 channels was fine back in the days of 1x200MB HD (and you had 1x3.5" floppy and 1x5.25" floppy) but in these days of 2xHDs, 1xCDRW and 1xDVD it is about time more channels were made standard.